In secondary school, and in fact in all schools, stop the bloody obession with data.
How well a child does at 11 gives an indication of what they might be capable of at 16 no more, and you have to have a discount for how much help and practice they were given in primary to achieve that grade, if in fact it is accurate.
At 16 the child may be very different, due to all sorts of factors, and setting a target is fine, but the adherence to the idea that the child should achieve that target or it is the teacher's fault is ridiculous.
Also, projected grades each half term. I can give you an idea of how your child is going to do, but especially with GCSEs and A levels I can't really give you an idea until we have finished delivering the entire course and they have done a proper mock or even two. Yes Martha and Henry might have done well in their test which covered a specific set of topics covered in the first half term, they may have done well in the second term too, but I'm buggered if I know if they'll do as well in the whole thing at that stage. It makes no sense.
I'm a trained economist, we know that data is an indicator not an absolute, so stop treating it as such and holding teachers accountable for it. We can't sit the exam, we can only facilitate, a big part of it is down to an uncontrollable set of variables.
For example, a lot of kids taking my subject at A level take maths. A few years ago the AS maths exam was on the morning prior to the econ exam on the afternoon, guess what? Some (not all) students who took both performed worse than expected in the later exam. The exam on the morning was an infulence. A child last year took 3 exams on one day, the econ exam last, she got an E when she had been hitting C/B borderline all year. Not a controlable or predictable factor using data yet we still had to explain why the data for her had been "wrong" all year.
Kind of glad I'm no longer front line all the time. Moving away from full time and going back into doing some subject related research has been a boon.